As a table unit of this type, for example, a technology described in PTL 1 is disclosed. In the technology described in PTL 1, a table unit is mounted on the back surface side of the backrest of a seat for a vehicle. The table unit includes a table main body that a passenger manually opens and closes.
The table main body is configured to be able to rotate about a fulcrum axis extending in the vehicle width direction from a housed attitude in which the table main body is folded to the backrest side to a use attitude in which the folding is released. In addition, a hinge mechanism including cam bodies is disposed in a fulcrum shaft portion of the table main body, and the table main body is configured to be able to, by means of the hinge mechanism, rotate from the housed attitude to the use attitude and retain the respective attitudes.